1. Field of the Invention
The present disclosure relates generally to medical and surgical devices, and more specifically to seal assemblies for cannulas.
2. Related Art
Arthroscopic or, more generally, endoscopic surgical procedures enable closed surgery to be performed via portals through which a variety of elongated instruments may be passed to gain access to an internal surgical work site. Very often a disposable cannula is inserted into the portal in order to provide a convenient passageway through which various instruments may be passed. Because many arthroscopic procedures require the use of pressurized fluid to distend and irrigate the joint being operated upon, the cannula must provide a sealed passageway in order to enable instruments to be passed into and out of the cannula while maintaining a fluid seal whether or not an instrument is in the cannula passageway. The sealing of such cannula passageways is usually accomplished by one or more elastomeric membranes attached to the proximal end of the elongated cannula.
Since the fluid at the work site is pressurized, care must be taken to avoid leakage during the time the instrument is being inserted. Current seal assemblies for use in cannulas leak excessively and improvement on the amount of leakage out of the cannula is desired. In addition, upon insertion of an instrument into an opening on the seals of current models, fluid sprays out of the opening. In order to prevent this from occurring, the seal is covered by placing a spray shield on the proximal end of the cannula. FIG. 1 shows a current cannula model 10 that has a spray shield 11 covering the seal assembly 12 at the proximal end 13 of the cannula 10. However, the size of the spray shield 11 makes it difficult for the surgeon to work in tight operative spaces. Therefore, a sealing assembly that minimizes this problem is also needed.
Furthermore, the variety of instruments which must be inserted through the cannula seal includes instruments of varying sizes and configurations. While the instrument shafts are usually cylindrical, some instruments may have unusually large or sharp distal tips which may cut a seal element upon the insertion or extraction of the instrument thus making it less suitable for subsequent instruments which must be inserted during the same surgical procedure. It is desirable, therefore, to devise a sealing cannula which minimizes this problem.
Finally, in addition to instruments, sutures may also be passed through the seal assembly. In fact, the management of these sutures has become critical to the technical success of the surgery. Indeed, tangled sutures can terminate an arthroscopic procedure. Therefore, an approach to suture management is also needed.